The goal of the present study is to characterize the functional properties of wide-field retinal amacrine cells as a model system for amacrine cell physiology. The proposed research is designed to study: (1) the intrinsic membrane properties of these cells after they have been isolated from the retina and maintained in culture; (2) the action of the neurotransmitters glutamate, GABA and glycine for their effect on the amacrine cell response properties; and (3) the interplay between neurotransmitter action and voltage-activated currents. In addition to the above transmitters, the action of the neuromodulator dopamine will also be examined. Following the studies on cultured cells, the retinal slice preparation will be used to investigate the physiological responses of amacrine cells in the context of a functioning retina. Stimuli will be presented and response properties evaluated. A ganglion cell receiving input from the wide-field amacrine cell will be identified, and signal transmission from the amacrine cell to ganglion cell will be studied. Information gathered from the proposed study will be valuable in understanding how signal processing occurs at the level of the last synaptic interface in the retina before information is transferred to the brain.